A. 6n+3n+10= 9n+10. Jordan is 9n+10 years old.
B. 6n+9n+10= 15n+10. The total age of Prince and Jordan is 15n+10.
C. 6n-9. Kimberly is 6n-9 years old.
D. (6n+9n+10)+6n-9 = 15n+10+6n-9 = 15n+6n+10-9 = 21n+1. The total age of Prince, Jordan and Kimberly is 21n+1
E. 21•(4)+1=84+1=85. The total age of Prince, Jordan and Kimberly is 85 years.